TM4SF1 (L6 antigen) notes

Deep research providers unavailable (no API keys). Notes from UniProt P30408 and cached literature.

Identity / topology

• TM4SF1 / tumor-associated antigen L6, member of the L6 tetraspanin (transmembrane 4 L six) family. Four
  transmembrane helices (10-30, 50-70, 94-114, 162-182) with short cytoplasmic N- and C-termini; the large
  extracellular loop (EC2, ~115-161) carries the N-glycosylation site and is the epitope of the L6 monoclonal
  antibody, i.e. surface-accessible.
• PMID:7510285.
• [UniProt P30408 "SUBCELLULAR LOCATION: Membrane; Multi-pass membrane protein. Note=Colocalizes with SDCBP2 in the apical region of the cell"].
• Localization conclusion: plasma membrane (multi-pass), apical in epithelia; EC2 loop exposed at the cell
  surface (antibody/therapeutic target). Not intracellular.

Function

• Poorly defined. Present in high-molecular-weight tumor-cell complexes; its C-terminal cysteine mediates
  interaction with the PDZ protein SDCBP2/SITAC PMID:11102519.
• Highly expressed in lung/breast/colon/ovarian carcinomas and on endothelial cells; implicated in angiogenesis
  and tumor progression (general knowledge, not annotation evidence).